Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for a circuit configured to perform computations using multiple inputs. The circuit includes multiple adder circuits and a selection circuit that includes multiple input selector. Each adder circuit performs an addition operation using sets of inputs derived from the multiple inputs. The input selectors are configured to select one or more inputs from a set of inputs derived from the multiple inputs based on a sign bit for an input in the set and pass the selected inputs to an adder circuit that generates a sum using the selected inputs. The circuit determines a routing of the sum to another adder circuit based in part on a sign bit for the input in the set of inputs.